It’s absolutely an issue. Easy to reproduce.
Create a chat tab for Guild and choose to have just Guild and Officer chat shown in that tab. Create a second tab called Group, and choose to show only party and instance chat in that tab.
Under both tabs you have all channels (Gen, Trade etc) unticked yet it will still show up in those tabs which it should not.
You can /leave the channels but then that takes you out of them completely so you don’t see the chat at all in the ALL tab so that’s not a solution.
If you log out and back in it rejoins you to all the channels and it all appears in all your created tabs again. Yet if you look at your created tab settings, those channels are still actually unticked and should not be showing in them.
There’s also another thread reporting this here: